Multichromatic near-infrared imaging to assess interstitial lymphatic and venous uptake in vivo

• Type of Material: Article
• Authors: Fabrice C Bernard, Georgia Institute of Technology; Jarred Kaiser, Emory University; Sarvgna K Raval, Emory University; Zhanna Nepiyushchikh, Emory University; Thanh Doan, Emory University; Nick Willett, Emory University; Brandon J Dixon, Georgia Institute of Technology
• Language: English
• Date: 2021-12-01
• Publisher: SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS
• Publication Version: Final Published Version
• Copyright Statement: © 2021 The Authors
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1117/1.JBO.26.12.126001
• Title of Journal or Parent Work: JOURNAL OF BIOMEDICAL OPTICS
• Volume: 26
• Issue: 12
• Grant/Funding Information: This research was funded in part by funding from the Department of Defense PRMRP Grant No. PR171379 and the National Institutes of Health National Heart, Lung, and Blood Institute, Grant No. R01HL133216.
• Keywords: lymphatic; Life Sciences & Biomedicine; NIR imaging; SYNOVIUM; Optics; PENETRATION; tissue optics; Biochemistry & Molecular Biology; CLEARANCE; MUSCLE; EXERCISE; Radiology, Nuclear Medicine & Medical Imaging; Biochemical Research Methods; FLOW; LIGHT; KNEES; Science & Technology; venous; Physical Sciences; clearance
• Research Categories: Engineering, Biomedical

Abstract

Significance: Changes in interstitial fluid clearance are implicated in many diseases. Using near-infrared (NIR) imaging with properly sized tracers could enhance our understanding of how venous and lymphatic drainage are involved in disease progression or enhance drug delivery strategies. Aim: We investigated multichromatic NIR imaging with multiple tracers to assess in vivo microvascular clearance kinetics and pathways in different tissue spaces. Approach: We used a chemically inert IR Dye 800CW (D800) to target venous capillaries and a purified conjugate of IR dye 680RD with 40 kDa PEG (P40D680) to target lymphatic capillaries in vivo. Optical imaging settings were validated and tuned in vitro using tissue phantoms. We investigated multichromatic NIR imaging's utility in two in vivo tissue beds: the mouse tail and rat knee joint. We then tested the ability of the approach to detect interstitial fluid perturbations due to exercise. Results: In an in vitro simulated tissue environment, free dye and PEG mixture allowed for simultaneous detection without interference. In the mouse tail, co-injected NIR tracers cleared from the interstitial space via distinct routes, suggestive of lymphatic and venous uptake mechanisms. In the rat knee, we determined that exercise after injection transiently increased lymphatic drainage as measured by lower normalized intensity immediately after exercise, whereas exercise pre-injection exhibited a transient delay in clearance from the joint. Conclusions: NIR imaging enables simultaneous imaging of lymphatic and venous-mediated fluid clearance with great sensitivity and can be used to measure temporal changes in clearance rates and pathways.